The large intestine extends from the ileum and ends at the anus. It forms the final part of the digestive tract. The large intestine is divided into the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum.

Food that is undigested proceeds into the large intestine from the small intestine. Here it reabsorbs water that is used in digestion and eliminates undigested food and fibre.

This organ enables the absorption of water, ions and vitamins, the forming of faeces and the excretion of solid waste material (defecating).

Rhythmic contractions along the smooth intestinal muscles, called peristalsis, push the food and waste matter along the length of the intestine. The waste matter is solid because most of the water is removed by the intestines as it travels through them.

Faeces are stored in the rectum until egested by the muscles of the anus. Bacteria found in the large intestine convert the proteins into amino acids. They also break down the amino acids resulting in some B vitamins and vitamin K.